In the past, there has been known a blood pressure measuring system (Japanese Patent publication [KOKOKU] No. 3-11219) utilizing an oscillometric method, which is characterized by extracting an arterial pulse component superimposed on a cuff pressure of each arterial pulse, and deriving particular times indicative of systolic and diastolic blood pressures in accordance with a variation of the arterial pulse component. In the blood pressure measuring system, the arterial pulse component is defined as a pulse height of the arterial pulse.
By the way, since the pulse height of each arterial pulse is varied in response to a bloodstream of a selected portion of a subject to which an occluding cuff is attached, an extent of the variation is influenced by individual difference. In particular, when the variation of the pulse height is small at a particular time indicative of the systolic or diastolic blood pressure of the subject, it is difficult to accurately derive the systolic or diastolic blood pressure from the pulse height. Therefore, there is a probability of causing an error of measurement.
A primary object of the present invention is to provide a blood pressure measuring system capable of accurately determining systolic and diastolic blood pressures of a subject while preventing the occurrence of an error of measurement.